LINEAR TECHNOLOGY LT3028 Technical data

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FEATURES

■

Low Noise: 20µV

■

Low Quiescent Current: 30µA/Output

■

Independent Inputs

■

Wide Input Voltage Range: 1.8V to 20V

■

Output Current: 100mA/500mA

■

Very Low Shutdown Current: <0.1µA

■

Low Dropout Voltage: 300mV/320mV at

(10Hz to 100kHz)

RMS

100mA/500mA

■

Adjustable Outputs from 1.22V to 20V

■

Stable with as Low as 1µF/3.3µF Output Capacitor

■

Stable with Aluminum, Tantalum or Ceramic Capacitors

■

Reverse-Battery Protected

■

No Protection Diodes Needed

■

Overcurrent and Overtemperature Protected

■

Tracking/Sequencing Capability

■

Thermally Enhanced 16-Lead TSSOP and 16-Lead (5mm × 3mm) DFN Packages

U

APPLICATIO S

■

Cellular Phones

■

Pagers

■

Battery-Powered Systems

■

Frequency Synthesizers

■

Wireless Modems

■

Tracking/Sequencing Power Supplies

LT3028

Dual 100mA/500mA

Low Dropout, Low Noise,

Micropower Regulators with

Independent Inputs

U

DESCRIPTIO

The LT®3028 is a dual, micropower, low noise, low dropout regulator with independent inputs. With an external

0.01µF bypass capacitor, output noise is a low 20µV over a 10Hz to 100kHz bandwidth. Designed for use in battery-powered systems, the low 30µA quiescent current per output makes it an ideal choice. In shutdown, quiescent current drops to less than 0.1µA. Shutdown control is independent for each output, allowing for flexibility in power management. The device is capable of operating over an input voltage range of 1.8V to 20V. Output 1 can supply 500mA of output current with a dropout voltage of 320mV. The device can supply 100mA of output current from Output 2 with a dropout voltage of 300mV. Quiescent current is well controlled in dropout.

The LT3028 regulator is stable with output capacitors as low as 1µF for the 100mA output and 3.3µF for the 500mA output. Small ceramic capacitors can be used without the series resistance required by other regulators.

Internal protection circuitry includes reverse-battery protection, current limiting and thermal limiting protection. The device is available as an adjustable device with a 1.22V reference voltage. The LT3028 regulator is available in the thermally enhanced 16-lead TSSOP and 16-lead, low profile (5mm × 3mm × 0.75mm) DFN packages.

, LTC and LT are registered trademarks of Linear Technology Corporation.

Protected by U.S. Patents including 6118263, 6144250.

RMS

TYPICAL APPLICATIO

3.3V/2.5V Low Noise Regulators

OUT1

V

3.7V TO 20V

V

2.9V TO 20V

IN1

IN2

1µF

IN1

SHDN1

IN2

SHDN2

LT3028

GND

BYP1 ADJ1

OUT2

BYP2 ADJ2

U

0.01µF 10µF 422k

249k

0.01µF 10µF 261k

249k

3028 TA01a

3.3V AT 500mA NOISE

20µV

RMS

2.5V AT 100mA NOISE

20µV

RMS

10Hz to 100kHz Output Noise

V

OUT

100µV/DIV

3028 TA01b

20µV

RMS

3028f

1

LT3028

16

15

14

13

12

11

10

9

17

1

2

3

4

5

6

7

8

ADJ1

SHDN1

IN1

IN2

SHDN2

ADJ2

BYP1

NC

OUT1

GND

OUT2

BYP2

TOP VIEW

DHC PACKAGE

16-LEAD (5mm × 3mm) PLASTIC DFN

WWWU

ABSOLUTE AXI U RATI GS

(Note 1)

IN1, IN2 Pin Voltage .............................................. ±20V

OUT1, OUT2 Pin Voltage ....................................... ±20V

Input-to-Output Differential Voltage....................... ±20V

ADJ1, ADJ2 Pin Voltage ......................................... ±7V

BYP1, BYP2 Pin Voltage ....................................... ±0.6V

SHDN1, SHDN2 Pin Voltage ................................. ±20V

Output Short-Circut Duration.......................... Indefinite

UU

W

PACKAGE/ORDER I FOR ATIO

TOP VIEW

1

GND

2

BYP1

3

OUT1

4

OUT1

GND

OUT2

BYP2

GND

16-LEAD PLASTIC TSSOP

T

= 150°C, θJA = 38°C/ W, θJC = 8°C/ W

JMAX

EXPOSED PAD (PIN 17) IS GND

MUST BE SOLDERED TO PCB

5

6

7

8

FE PACKAGE

17

GND

16

ADJ1

15

SHDN1

14

IN1

13

IN2

12

SHDN2

11

ADJ2

10

GND

9

ORDER PART

NUMBER

LT3028EFE LT3028IFE

FE PART

MARKING

3028EFE 3028IFE

Operating Junction Temperature Range

(Note 2) ............................................ –40°C to 125°C

Storage Temperature Range

FE Package ....................................... – 65°C to 150°C

DHC Package .................................... – 65°C to 125°C

Lead Temperature (Soldering, 10 sec).................. 300°C

ORDER PART

NUMBER

LT3028EDHC LT3028IDHC

DHC PART

MARKING

3028

T

= 125°C, θJA = 40°C/ W, θJC = 10°C/ W

JMAX

EXPOSED PAD (PIN 17) IS GND

MUST BE SOLDERED TO PCB

3028I

Consult factory for parts specified with wider operating temperature ranges.

ELECTRICAL CHARACTERISTICS

The ● denotes specifications which apply over the full operating temperature range, otherwise specifications are TA = 25°C. (Note 2)

PARAMETER CONDITIONS MIN TYP MAX UNITS

Minimum Input Voltage Output 2, I (Notes 3, 10) Output 1, I

ADJ1, ADJ2 Pin Voltage VIN = 2V, I (Notes 3, 4) Output 2, 2.3V < V

Line Regulation (Note 3) ∆VIN = 2V to 20V, I

Load Regulation (Note 3) Output 2, V

2

= 100mA ● 1.8 2.3 V

LOAD

= 500mA ● 1.8 2.3 V

LOAD

= 1mA 1.205 1.220 1.235 V

LOAD

Output 1, 2.3V < V

= 2.3V, ∆I

IN2

= 2.3V, ∆I

V

IN2

Output 1, V

IN1

V

IN1

= 2.3V, ∆I = 2.3V, ∆I

< 20V, 1mA < I

IN2

< 20V, 1mA < I

IN1

= 1mA ● 110 mV

LOAD

= 1mA to 100mA 1 12 mV

LOAD

= 1mA to 100mA ● 25 mV

LOAD

= 1mA to 500mA 1 12 mV

LOAD

= 1mA to 500mA ● 25 mV

LOAD

< 100mA ● 1.190 1.220 1.250 V

LOAD

< 500mA ● 1.190 1.220 1.250 V

LOAD

3028f

LT3028

ELECTRICAL CHARACTERISTICS

The ● denotes specifications which apply over the full operating temperature range, otherwise specifications are TA = 25°C. (Note 2)

PARAMETER CONDITIONS MIN TYP MAX UNITS

Dropout Voltage I (Output 2) I

V

= V

IN2

OUT2(NOMINAL)

(Notes 5, 6, 10)

Dropout Voltage I (Output 1) I

V

= V

IN1

OUT1(NOMINAL)

(Notes 5, 6, 10)

GND Pin Current I (Output 2) I V

= V

IN2

OUT2(NOMINAL)

(Notes 5, 7) I

GND Pin Current I (Output 1) I V

= V

IN1

OUT1(NOMINAL)

(Notes 5, 7) I

Output Voltage Noise C

ADJ1/ADJ2 Pin Bias Current ADJ1, ADJ2 (Notes 3, 8) 30 100 nA

Shutdown Threshold V

SHDN1/SHDN2 Pin Current V (Note 9) V

Quiescent Current in Shutdown VIN = 6V, V

Ripple Rejection VIN = 2.72V (Avg), V

Current Limit Output 2, V

Input Reverse Leakage Current VIN = – 20V, V

Note 1: Absolute Maximum Ratings are those values beyond which the life of a device may be impaired.

Note 2: The LT3028 regulator is tested and specified under pulse load conditions such that T

≈ TA. The LT3028E is guaranteed to meet

J

performance specifications from 0°C to 125°C junction temperature. Specifications over the –40°C to 125°C operating junction temperature

= 1mA 0.10 0.15 V

LOAD

= 1mA ● 0.19 V

LOAD

I

= 10mA 0.17 0.22 V

LOAD

I

= 10mA ● 0.29 V

LOAD

I

= 50mA 0.24 0.31 V

LOAD

I

= 50mA ● 0.40 V

LOAD

I

= 100mA 0.30 0.35 V

LOAD

I

= 100mA ● 0.45 V

LOAD

= 10mA 0.12 0.19 V

LOAD

= 10mA ● 0.25 V

LOAD

I

= 50mA 0.17 0.22 V

LOAD

I

= 50mA ● 0.32 V

LOAD

I

= 100mA 0.21 0.28 V

LOAD

I

= 100mA ● 0.34 V

LOAD

I

= 500mA 0.32 0.37 V

LOAD

I

= 500mA ● 0.47 V

LOAD

= 0mA ● 25 50 µA

LOAD

= 1mA ● 60 95 µA

LOAD

I

= 10mA ● 230 400 µA

LOAD

= 50mA ● 12 mA

LOAD

I

= 100mA ● 2.2 4 mA

LOAD

= 0mA ● 30 75 µA

LOAD

= 1mA ● 65 120 µA

LOAD

I

= 50mA ● 1 1.6 mA

LOAD

= 100mA ● 23 mA

LOAD

I

= 250mA ● 58 mA

LOAD

I

= 500mA ● 10 16 mA

LOAD

= 10µF, C

OUT

= 0.01µF, I

BYP

= Full Current, 20 µV

LOAD

RMS

BW = 10Hz to 100kHz

= Off to On ● 0.80 1.4 V

OUT

V

= On to Off ● 0.25 0.65 V

OUT

, V

SHDN1

, V

SHDN1

I

= Full Current

LOAD

Output 1, V

= 0V ● 0 0.5 µA

SHDN2

= 20V ● 1 3.0 µA

SHDN2

= 0V, V

SHDN1

RIPPLE

= 7V, V

IN2

V

IN2

IN1

V

IN1

OUT2

= 2.3V, ∆V

= 7V, V

OUT1

= 2.3V, ∆V

= 0V ● 1mA

OUT

= 0V 0.01 0.1 µA

SHDN2

= 0.5V

P-P

, f

= 120Hz, 55 65 dB

RIPPLE

= 0V 500 mA

= –0.1V ● 110 mA

OUT2

= 0V 1.3 A

= –0.1V ● 520 mA

OUT1

range are assured by design, characterization and correlation with statistical process controls. The LT3028I is guaranteed and tested over the full –40°C to 125°C operating junction temperature range.

Note 3: The LT3028 is tested and specified for these conditions with the ADJ1/ADJ2 pin connected to the corresponding OUT1/OUT2 pin.

3028f

3

LT3028

ELECTRICAL CHARACTERISTICS

Note 4: Operating conditions are limited by maximum junction temperature. The regulated output voltage specification will not apply for all possible combinations of input voltage and output current. When operating at maximum input voltage, the output current range must be limited. When operating at maximum output current, the input voltage range must be limited.

Note 5: To satisfy requirements for minimum input voltage, the LT3028 is tested and specified for these conditions with an external resistor divider (two 250k resistors) for an output voltage of 2.44V. The external resistor divider will add a 5µA DC load on the output.

Note 6: Dropout voltage is the minimum input to output voltage differential needed to maintain regulation at a specified output current. In dropout, the output voltage will be equal to: V

IN

– V

DROPOUT

.

Note 7: GND pin current is tested with V load. This means the device is tested while operating in its dropout region or at the minimum input voltage specification. This is the worst-case GND pin current. The GND pin current will decrease slightly at higher input voltages. Total GND pin current is equal to the sum of GND pin currents from Output 1 and Output 2.

Note 8: ADJ1 and ADJ2 pin bias current flows into the pin. Note 9: SHDN1 and SHDN2 pin current flows into the pin. Note 10: For the LT3028 dropout voltage will be limited by the minimum

input voltage specification under some output voltage/load conditions. See the curve of Minimum Input Voltage in the Typical Performance Characteristics.

UW

TYPICAL PERFOR A CE CHARACTERISTICS

Output 2 Typical Dropout Voltage

500

450

400

350

300

250

200

150

DROPOUT VOLTAGE (mV)

100

50

0

0 102030

40

OUTPUT CURRENT (mA)

TJ = 125°C

TJ = 25°C

60 70 80 90 100

50

3028 G01

Output 2 Guaranteed Dropout Voltage

500

= TEST POINTS

450

400

350

300

250

200

150

DROPOUT VOLTAGE (mV)

100

50

0

0 102030

TJ ≤ 125°C

TJ ≤ 25°C

40

50

OUTPUT CURRENT (mA)

60 70 80 90 100

3028 G02

= 2.44V and a current source

IN

Output 2 Dropout Voltage

500

450

400

350

300

250

200

150

DROPOUT VOLTAGE (mV)

100

50

0

–50

–25

IL = 100mA

25

0

TEMPERATURE (°C)

IL = 50mA

IL = 10mA

IL = 1mA

50

100

125

3028 G03

75

Output 1 Typical Dropout Voltage

500

450

400

350

300

250

200

150

DROPOUT VOLTAGE (mV)

100

50

0

0 50 100 150

OUTPUT CURRENT (mA)

4

TJ = 125°C

TJ = 25°C

200

300 350 400 450 500

250

3028 G04

Output 1 Guaranteed Dropout Voltage

500

= TEST POINTS

450

400

350

300

250

200

150

100

50

GUARANTEED DROPOUT VOLTAGE (mV)

0

0 50 100 150

TJ ≤ 125°C

TJ ≤ 25°C

200

300 350 400 450 500

250

OUTPUT CURRENT (mA)

3028 G05

Output 1 Dropout Voltage

500

450

400

350

300

250

200

150

DROPOUT VOLTAGE (mV)

100

50

0

–50

I

= 50mA

L

–25

I

= 100mA

L

0

25

TEMPERATURE (°C)

= 250mA

I

L

IL = 10mA

50

IL = 500mA

IL = 1mA

75

100

125

3028 G06

3028f

UW

TYPICAL PERFOR A CE CHARACTERISTICS

LT3028

Quiescent Current (Per Output)

50

45

40

35

30

25

20

15

QUIESCENT CURRENT (µA)

10

5

0

VIN = 6V

= 250k, IL = 5µA

R

L

–50

V

= V

SHDN

IN

050–25 25 75 125

TEMPERATURE (°C)

Output 2 GND Pin Current

2.50

2.25

2.00

1.75

1.50

1.25

1.00

0.75

GND PIN CURRENT (mA)

0.50

0.25

0

0123

RL = 12.2Ω I

= 100mA*

L

RL = 1.22k

= 1mA*

I

L

4

5

INPUT VOLTAGE (V)

RL = 24.4Ω I

L

100

3028 G07

TJ = 25°C *FOR V

= 1.22V

OUT

= 50mA*

RL = 122Ω

= 10mA*

I

L

678910

3028 G10

ADJ1 or ADJ2 Pin Voltage Quiescent Current (Per Output)

1.240 IL = 1mA

1.235

1.230

1.225

1.220

1.215

ADJ PIN VOLTAGE (V)

1.210

1.205

1.200

–25 25 75 125

–50

050

TEMPERATURE (°C)

100

3028 G08

40

TJ = 25°C

= 250k

R

L

35

30

25

20

15

10

QUIESCENT CURRENT (µA)

5

0

42 6 10 14 18

0

INPUT VOLTAGE (V)

V

SHDN

V

SHDN

8

Output 2 GND Pin Current vs I

2.50 VIN = V

OUT(NOMINAL)

= 25°C

T

2.25

J

2.00

1.75

1.50

1.25

1.00

0.75

GND PIN CURRENT (mA)

0.50

0.25

0

0 102030

OUTPUT CURRENT (mA)

+ 1V

40

50

LOAD

60 70 80 90 100

3028 G11

Output 1 GND Pin Current

1200

1000

800

600

400

GND PIN CURRENT (µA)

200

0

0123

RL = 24.4Ω

= 50mA*

I

L

RL = 122Ω

= 10mA*

I

L

RL = 1.22k

= 1mA*

I

L

4

INPUT VOLTAGE (V)

5

= V

IN

= 0V

12

16

20

3028 G09

TJ = 25°C

= V

V

IN

SHDN

*FOR V

= 1.22V

OUT

678910

3028 G12

Output 1 GND Pin Current

12

10

RL = 2.44Ω

= 500mA*

I

8

6

4

GND PIN CURRENT (mA)

2

0

0123

L

4

INPUT VOLTAGE (V)

TJ = 25°C

= V

V

IN

SHDN

*FOR V

5

= 1.22V

OUT

RL = 4.07Ω

= 300mA*

I

L

RL = 12.2Ω

= 100mA*

I

L

678910

3028 G13

Output 1 GND Pin Current vs I

12

VIN = V

OUT(NOMINAL)

= 25°C

T

J

10

8

6

4

GND PIN CURRENT (mA)

2

0

0 50 100 150

OUTPUT CURRENT (mA)

+ 1V

200

300 350 400 450 500

250

LOAD

3028 G14

SHDN1 or SHDN2 Pin Threshold (On-to-Off)

1.0 IL = 1mA

0.9

0.8

0.7

0.6

0.5

0.4

0.3

SHDN PIN THRESHOLD (V)

0.2

0.1

0

–50

–25

0

TEMPERATURE (°C)

50

25

100

125

3028 G15

3028f

75

5

LINEAR TECHNOLOGY LT3028 Technical data

Specifications and Main Features

Frequently Asked Questions

User Manual